Update Slurm Launcher

[haileyschoelkopf]

This PR changes the the SLURM launcher in two ways:

1. Due to what looks like a unintended consequence of a merge commit, self.args.slurm_comment was still referenced, and the launcher would include --comment even when self.args.comment was an empty string.
2. We now want to be using --account rather than --comment for assigning accounting groups to a given job. (if this is too specific to the Stability cluster, happy to find some way to allow users to toggle between using --account and --comment

I've left the comment argument in GPT-NeoX with its same name, but can update it to something like slurm_account if that is preferred.

cc @Quentin-Anthony

[Quentin-Anthony]

if this is too specific to the Stability cluster
This is a bit too specific and is misleading since we define a slurm comment arg, then pass it as a slurm account:

srun_cmd += ['--account', self.args.comment]

Slurm defines both an account and a comment arg, so let's allow for either/both? Let's add a new account argument, preserve the current comment arg, and expose both in gpt-neox

[haileyschoelkopf]

Makes sense to me! Will adjust.

[haileyschoelkopf]

Updated and added PR to NeoX here: EleutherAI/gpt-neox#1126